If you have DAC-9, wait for the CDT-9, unless you want to try different sound.
Before we go into the debate about DAC chips, I will state that the leading DAC chips from AKM and ESS have advanced so much that it is now just a matter of preference. We experimented with various newer ESS chips (variants of 9028 and 9038) and find that they make little difference in sound. IDA-32 was planning to use 9038 but didn't sound as pleasing as 9028 so we went with 9028. We could have used 9018 but then customers wanted the newer chip so fortunately 9028 sounded just as good as 9018.
Now with the back story out of the way, CDP-9 uses ESS9028. ESS chips are more neutral than AKM that DAC-9 used.
On the website there is an FAQ about preamp and power supply now becoming the dominant factor in high end DAC performance.
CDP-9 over performance is closer to DAC-10 than DAC-9.